Apparatus for grinding discontinuous segmental surfaces



F. A. -WARDI Jan. 8; 1935..

APPARATUS FOR GRINDING DISCONTINUOUS SEGMENTAL SURFAQES Filed June 25,'7 Sheets-Shet 1 l liar INVENTOR gcz) z: 1% Wk/J BY W ATTORN EYS Jan. 8,1935. A, 'WARD 1,987,222

APPARATUS FOR GRINDING DISCONTINUOUS SEGMENTAL SURFACES Filed June 23,1950 7 Sheets-Sheet 2 INVENTOR BY W ATTORN EYS Jan. 8, 1935. F. A. WARD1,987,222

APPARATUS FOR GRINDING DISCONTINUOUS SEGMENTAL SURFACES Filed June 25,1930 '7 Sheets-Sheet 3 INVENTOR 136 a? aria/F ,4. 72214 av WM ATTO RNEYFS F. A. WARD Jan. 8, 1935.

APPARATUS FOR GRINDING DISCONTINUOUS SEGMENTAL SURFACES Filed June 23,1930 '7 Sheets-Sheet 4 INVENTOR My? fleaferz'af/f.

BY W

ATTO RN EYS Jan. 8, 1935. F. A. WARD 1,987,222

APPARATUS FOR GRINDING DISCONTINUOUS SEGMEINTAL SURFACES Filed June 23,1930 7 Sheets-Sheet 5 V ATTORNEYS Jan- 8, 93 RA.- WARD 1,987,222

7 APPARATUS FOR GRIEDING DISCONTINUOUS SEGMEN'I'AL SURFACES A Filed June23, 1950 7 Sheets-Sheet 6 Tqll. T1

QR $.20- f 24 L INVENTOR g 2W2 3 v 1 1H 1 111 M A// %%W%%%WWWW%%% F. A.WARD Jan. s, 1935.

APPARATUS FOR GRINDING DISCONTINUOUS SEGMENTAL SURFACES Filed June 23,1950 7 Sheets-Sheet '7 ATTORNEY-8 about a common side and-withintermediate ob- Patented Jan- 8, 1935 APPARATUS FOR ammo nrscom'mu- T'OFFICE OUS SEGMENTAL SURFACES Frederick A. Ward, Detroit, Mich.,'assignor to The Gear Grinding Machine Company, Detroit, Mich., acorporationof'ltlichigan I Application is 23,1930; No. 463,180

Theinvention relates to the grinding of articles having discontinuoussegmental surfaces arranged structions. It is the primary object of theinvention to facilitate the rapid grinding of the articles and at thesame time to secure a high degree of accuracy both in the groundsurfaces and their relation to a predetermined axis in the article. Itis a further object to obtain a machine so constructed and organizedthat "its functions are autoy matically performed with little attentionfrom the operator other than .to place the articles in the machine andto remove them after completion of the work.

My improvements are applicable to the grinding of a large variety ofarticles but I shall specifically describe a single use, viz.: thegrinding of an article having cylindrical segments interrupted byprojecting wings and axially concentric with -a cylindrical shaft. Thesaid structure is designed. for use in a hydraulic shock absorber whereit is highly essential thatthe shank,;tl1e peripheral surfaces of'thewings and the segmental surfaces intermediate the wings should with acommon axis. r

In my prior patents, Nos. 1.271395 and 1,155,532 I have described amethod and apparatus. for grinding interrupted segmental surfaces suchfor instance as spline shafts, this consisting essentially in thetrimming'of a grinder wheelto the desired cross sectional contour andthe feeding of.

. be concentric the work axially in operative relation'to. said igrinder together with an indexing mechanism for successively registeringthe segments to be ground with such apparatus. The grinding of thedifl'er-. ent segments is-necessarily successive which limits the outputwhile the necessity of an indexing mechanism complicates theconstruction. It is therefore an object of the present invention toobtain a construction in which the grinding of a plurality of segmentsarranged about a common axis is simultaneously performed without anyinterference or loss in accuracy.

Generally described, my improved machine comprises a plurality ofgrinder wheels rotating in planes which intersect a common axistransverse to the axes of said grinder wheels, A work holder andatrimmer are arranged concentric with this axis and are moved along thesame into operative relation with said grinder wheels from oppositesides thereof. There is also provided means for periodically feeding thegrinder wheels towards each other and in simultaneously feeding thetrimmer into operative relation thereto and rotating the same to trimthe grinding SWIMW- its in, the operation of the same after the wheelshave been trimmed the articles to be 'ground'aresuccessively placed inthe holder and moved past the grinders while periodically the wheels arefed towards each other and are retrimmed; 1

To perform the functions just described I have designed and organized amachine which after each article of work is placed therein willautomatically perform the successive functions. These include the rapidmovement of the work from position of engagement. with its holder to thepoint of engagement with the grinder wheels, the slow feeding of thework during the grinding operation, the slowreturn'movement of the workpast the grinder wheels andthe rapid return to the position fordisengagement of the finished product and the engagement of the newarticle to beground. The mechanism also includes automatic meansoperating only occasionallyv or once for a predetermined, number of workcycles which feedsz the.

grinder wheels inward or towards eachotherl for a predetermined amountand then advances. th'e trimmer into operative relation to the grinderwheels and rotates thetrimmerin this position to street the trimming.The trimmer is then retracted to be out of the way :of the work inthesubsequent operation of the machine.

k The .detailedoonstruction'of the machine is preferably .as {shown inthe accompanying drawingsin which: I" v e v Figure 1 is a frontelevation; Figure 2'is an end elevation thereof:- Y Figure 3 is a crosssection "inthe plane of the axisof thetrimmer shaft: Y

Figure 4 is a perspectiveviewpf the work to be groundr; I

Figure *5 is ,a mechanism and controlling valve;

Figure 6 is a sectional elevation ofthetrinimer controlling mechanismand timing means there for;

sectional elevation of the Figure '7 is a horizontal section showingadjusting mechanism for the grinder wheels;

Figure 8 is a sectional elevation thereof; Figure 9 is a section on line9-9 of Figure 8;

Figure 10 is a section on line 10- -10 ofrFigure I;

Figure 11- is a vertical ll-11 of Figure 1;

Figure 12 is a horizontal section.- on line 12-12 of'Figure 3; Figure 13is a sectional elevation of the fluid pumping mechanism;

Figures 14 and 15 are detailed sections of portions of Figure 5'showingthe parts in different positions of adjustment;

cross section on line I Figure 16 is an elevation of the fluid conduitsystem showing the frame of a machine in dotted lines in relationthereto.

As illustrated, 1 is a frame upon which the various operating parts ofthe machine are mounted. 2 is a work supporting head which is in theform of a shelf or bracketvertically slidable upon a guideway 3 on thefront face of the frame 1. 4 and 4a are grinder wheels which are mountedupon arbors 5 journailed in heads 6 which are slidably mounted on ahorizontal guideway 7 on top of the frame 1. The grinder wheels 4 and 4arevolve in a common plane which is parallel to the plane of the guideway3 which latter is also perpendicular to the common axial plane of thearbors 5. Mounted on the top of the frame 1 centrally between the heads6 is-a bracket arm 8 which extends outward and is provided on its outerface with a vertical guideway 9 for a slidable head 10. The head 10 isprovided with a journal bearing for the trimmer shaft 11, the axis ofwhich lies in a plane which is centrally between the axes of thegrinders 4 and 40. At the lower end of the shaft 11 is a transverselyadJustable holder 12 for the diamond trimmer point 13, the arrangementbeing such that as will be hereinafter described in detail, the loweringof the head 10 will bring said diamond point in trimming relation to thegrinder wheels.

Work to be ground The specific article to be ground is illustrated inFigure 4 and comprises a shank or shaft por-' tion 14 with a pair ofdiametrically opposite 'projecting wings 15 having outer segmentalcylindrical surfaces 16 which are concentric with the axis of the shaft.Intermediate the wings 15 are segments 1'7 which are of a larger radiusthan the shaft 14 but which must be finished to beexactly concentricwith the axis of said shaft and of the peripheral segments 1'3. Theshaft 14 and the segments 16 may befinished in a lathe or other similartool and it is only the finishing of the segments 1'! which is performedby my grinding machine.

Work holder- 6 Upon the bracket head 2 is a work holder 18 which isprovided with a socket 19 for receiving and exactly fitting-the shank orshaft the work. Upon opposite sides of this socket 19 are clamping bars20 provided with hooks 21 at their upper ends for engaging the wings 15of the work. The hooks 21 are spaced from each other by a distance whichis greater than the diameter of the segments 17 so that the shank 14 maybe.

' 6 readily inserted in the socket 19 after which it may berevolvedthrough a quarter revolution to bring the wings 15 beneath the hooks 21.The bars 20 extend through the base of r the holder 18 and through theshelf of the bracket 2 having sleeved on their lower ends springs 22engaging collars 23 which act to draw the bars downward and to clamp thehooks 21 upon the wings 15. However, in the'normal position of thebracket head 2 the lower ends of the rods 20 engage. stationary stops 24so as to compress the springs 22 and to raise the hooks 21 a sufficientdistance to clear the wings 15. This permits of engaging the work withthe holder but upon the upward movement of the 2; the

springs 22 will clamp the hooks 21 upon the wings thereby holding thearticle from displacement.

Work setting means moving said holder upon the bracket head 2 in onedirection and adjustment screws 26 for moving the holder 18 upon thebracket head 2 in a transverse direction. By means of these twoadjustments the axis of the shaft 14 may be adjusted -to be coincidentwith the axis of the trimmer shaft 11 abovereferred to.

=W0rk feeding means To raise the bracket head 2 so as to bring the workinto operative relation to the grinders I have provided a hydraulicmotor comprising a cylinder 27 mounted on a projecting base portion 28of the frame 1. Within this cylinder is a piston 29 which is connectedby a piston rod 30 passing through a bearing 31 with the shelf portionofthe bracket head 2.. Thus if hydraulic fluid is admitted to the'lowerend of the cylinder 27 it will force the piston 29 upward carrying withit the bracket head 2 which slides on the guide bearing 3 and liftingthe work holder 18.

Feed control The fluid, preferably oil, which is used as the motiveagent is placed under pressure by the operation of a hydraulic pump 32of any suitable construction. As shown, this pump is driven from anelectric motor 33through the medium of a gear train 34 and delivers theoil under the desired pressure to the. controlling valve 35. This valveis preferably of the piston type and includes a cylinder 36 containing apiston having balancin heads 37 and 38 between which thepressure oil isadmitted to the cylinder as indicated at 350. 39 is a port in thecylinderconnected to a conduit 40 which leads to the base of thecylinder 2'! and 41 is a port connected to an exhaust conduit 42 for thereturn of the oil to the storage tank.

The valve has a stem 43 extending out of the cylinder and connected to abell crank lever 44 which is actuated by a second bell crank lever 45having on one of its arms the trip handle 46. The arrangement is suchthat the handle 46 will move the bell crank lever between the stop pins47 and 48 and through the medium of a pin 49 on the lever 44 willactuate the latter to depress the valve stem 43. This will shift theheads 3'! and 38 so as-to connect .the port 39 with thepressure oilwhich is thus admitted to the cylinder 27 to raise the piston 29. Theinitial actuation of the valve will open an unrestricted passage throughthe port 39 so that the piston 29 in the cylinder 27 is rapidly raisedto carry the work holder and the work into proximity-to the grinderwheels. The valve is temporarily held in this position by a latch ordetent 50 on a bell crank lever 51 and which engages with the upper endof the bell crank lever 44. Before, however, the work comes into actualcontact with the grinders a trip lug 52 on the bracket crank lever 51again arrests movement. The lat-.

ter stop is sc -positioned that the head as of the valve will cover thegreater portion of the area of the port 39 as indicated at 38a but willleave a suflicient opening in communication with the pressure oil tocontinue the upward movement of the piston at a slow speed; When thetravel of the piston is sufficient to pass the ,work beyond the grinderwheels a trip lug 56 again actuates the bell crank lever 51 to releasethe lever 44 and to permit it to contact with a third detent 57. This isso positioned that the head 38 of the valve will completely closeconnection betweenthe pressure oil and the port 39 but will leave arestricted opening in said port which communicates with the cylinderbelow the head 38 and with the exhaust conduit 42 as indicated at 38b.Thus the weight of the bracket head 2 will force the oil slowly from thecylinder 27 while the work in the holder is again passing the grinderwheels. Finally, after the work has passed the grinder wheels,

a trip lug 58 actuates the bell crank lever 51 to release the bell cranklever 44 from the stop or detent 57 and to permit the valve to resumeits normal position. Here the port 39 is unrestricted so that the oil inthe cylinder 2'1 may be rapidly exhausted with a correspondingly quickmovement downward of the head 2 and the work holder.

Trimmer operating mechanism As has been stated, it is only necessary totrim the grinder wheels occasionally as they will maintain their trueform during the grinding of a number of successive articles. I havefurther provided a timing mechanism which once in a predetermined numberof work cycles will set into op eration the trimming mechanism. Thiscomprises a ing 59 on the head 2 preferably on the reverse side or tothe left in Figure 1. This lug during each upward movement of the head 2will actuate a bell crank lever 60 which is connected by a link 61 witha ratchet lever 62 having a pawl 63 engaging a notched ratchet wheel 64.This ratchet wheel is connected to'a rotary cam 65 which once in eachrevolution will contact with a roller 66 on a lever arm 6'1, whichlatter is connected tov the stem 68 of a piston control valve 69. Thisvalve lowering of the trimmer shaft to bring the dia-{ mond trimmerpoint in the axial plane of the grinder wheels; second, the imparting ofrotary motion to the trimmer shaft so as to revolve the diamond pointbetween the grinder wheels; third, the feeding'of the heads 6 and 6atoward each other on the guideway 7 so as to adjust the grinder wheels 4and 4a slightly nearer to each other. These several'functions are allperformed by the valve in co-operation with mechanism 'of the followingconstruction.

Trimmer shalt raising and lowering mechanism As previously described,the trimmer shaft 11 is journalled in bearings in a vertically slidablehead 10 engaging a guideway 9 on the bracket arm 8. The slidable head 10is actuated by a lever 70 which is pivoted at 71 in a recess in thebracket arm 8 and extends into a recess in the slidable head 10 having aforked end '12 engaging a cross pin '13. Extending vertically andtransverse to contact with the walls of the slot while permittingangular movement of the lever. The upper end of the cylinder 74 isconnected by a conduit '18 and an extension conduit 79 with a port'80 inthe cylindrical valve casing 69. The valve cylinder is also suppliedwith oil under pressure through. a. port 81 which is connected by aconduit 81- leading from the pump or oil pressure chamber. This port isso located as to lie between the heads 82 and 83 of the ,valve pistonand in the normal position of the latter is out of communication withthe port 80. When, however, the cam65 depresses the roller 66 and rocksthe lever 67, this through the stem 68 will raise the valve piston,moving the head 82 above the port and establishing communication betweenthe pressure port 81 and said port 80 as shown in Fig. 6. This permitsthe fluid under pressure to travel through the conduits '19 and 78 intothe upper end of the cylinder 74 and to move the piston 76 downwardcarrying with it .the lever 70 and the slide 10. Downward movement ofthe slide 10 is arrested by an adjustable stop 84 which is so positionedthat the diamond point 13 will lie in the axial plane of the grinderwheel arbors 5. Movement of the piston 76 is retarded before contact ofthe slide 10 with the stop 84 by tapering pins 76a at opposite ends ofthe piston which engage with the ports and restrict flow of fluidexhausted from the cylinder 74 to produce a cushioning effect.

Trimmer rotating means' Mounted at the upper end of the slide 10 is acasing 85 of a rotary hydraulic motor for revolving the trimmer shaft11. This motor is preferably of the gear type comprising theintermeshing gear wheels 88 and 87 respectively iom'nalled on the shaft88 and mounted on the shaft 89. The shaft 89 is connected by spiralreduction gears 90 and 91 with the trimmer shaft 11, the

arrangement being such that the rotary motion generated by the gear pumpis transmitted at low angular speed to the shaft 11. The gear pump issupplied with motive fluid through a ,cor' duit 92 leading from thevalve 69 and coupled performs several distinct functions, viz: First,the ,4

by a flexible conduit 93 with the gear motor housing 85. 'Ihe valve isprovided with two additional piston heads 94 and 95 between which islocated an inlet port 96 for the fluid under pressure. A port 97 in thevalve cylinder communicates with the conduit 92cc that when the valve isin the position for supplying fluid to the port 89 it will also supplyfluid through the port 9'! to the conduits 92 and 93, thereby actuatingthe gear motor and revolving the trimmer shaft 11. This motion continuesas long as the valve remains in such position but whenever the cam 65disengages from the roller 66 the valve piston will be moved downward bythe actuation of a spring 98 which will simultaneously cut oil thepressure fluid from the ports 80 and 97. there y stopp n revolution ofthe trimmer shaft 11. At the same time the valve will establishconnection between the port 80 and an exhaust port 99 which through thechannel 100 connects with the exhaust conduit 4 101 returning to the oilstorage. In this same position of the valve the pressure port 81 will bein communication with-a port 102 in betweenthe heads 82 and 88 whichport connects through the conduit 103 and extension 104 with the lowerend of the cylinder 74 admitting fluid under pressure to said cylinderand lifting the piston l6, slide 10 and trimmer shaft mounted thereon.

Grinder wheel vadiustment In order that the trimming of the worn grinderwheels'may be effected, it is necessary to adjust these wheels towardseach other. This is accomplished by feed screws 105 which are journaledin end thrust bearings on opposite ends of the main frame and extendparallel to the guide '1 engaging nuts 106 on the heads 6 and 6a. Thescrews 105 are rotated through the medium of a reduction worm gearingcomprising the worm wheel 107 on the shank of the screwand a worm 108 ona transversely extending shaft 109. The

116 also engaging the ratchet wheel serves to holdthe latter fromreverse movement. The memher 114 is coupled with a pinion 117 which isin mesh with a rack 118 formed in a piston 119 slidable in a cylinder120. The opposite ends of this cylinder have connected thereto theconduits 121 and 122 which lead to the valve 69 and are so connectedthat in each actuation of said valve fluid underpressureis firstadmitted to one end of the cylinder 120 and then to the other endthereof, the first end being coupled with the exhaust. As a consequencethe piston 119 will be caused to reciprocate and when moved in onedirection will through the medium of the oscillatory arm 114 and pawl115 communicate rotary motion to the ratchet wheel 113 and shafts 111.This in turn will be transmitted through the miter gear wheels 110,shafts 109 and worm gearing 107 and 108 to the screw shafts 105. Byreason of the great reduction in angular speed through the worm gearingthe amount of rotary movement imparted to the shafts 105 is very Vslight but is enough to adjust the grinder wheels the required amountfor trimming.

General operation of the machine The grinder wheels 4 and 4a are drivenat the proper speed preferably by independent electric motors located asindicated at 123 and 124 and connected by belts 125 with the pulleys 126on the grinder arbors. The pump 32 for the hydraulic fluid is driven bya third electric motor 33 as before described, the supply of fluid beingcontained in'a chamber within the frame of the machine from which it is'drawn to the pump through a suction conduit 127'. The desired pressureis maintained on the line by the operation of a pressure relief valve128 which permits the surplus fluid to be returned to thestorage.

The motors being set in operation, the operator takes an article to beground and inserts the shank or shaft portion 14 thereof between thehooks 21 into engagement with the socket 19. The wings 15 are thenturned to a quarter of a revolution to be beneath the hooks 21 whichlatter are raised by the engagement of the lower ends of the bars 20with the stops 24. The operator then moves upward the handle 46 whichrocks the bell crank lever 44 depressing the stem 43 of the valveagainst the tension of the spring 54. The successive functions are thenautomatically performed as has been previously described in detail,effecting first the rapid upward movement of the work into proximitytothe grinder wheel; second, the

slow movement of the work upward between the grinder wheels, theperipheral surfaces of which have been 'preformed'to produce the exactform and dimensions in the ground surfaces. The work is then slowlymoved downward past the grinder wheels and then rapidly returned to itsinitial position.' In this positionv the rods 20 re-engage the stops 24,lifting the hooks 21 and releasing the work so that it maybe removed byfirst totating through a quarter revolution and then 1 lifting out ofthe socket 19. A second article is then placed in the socket andoperation is repeated by again drawing upward the operating handle 46.

After a predetermined number of work cycles, 15 i the successiveactuations of the bell crank arm ,60 by the lug 59 on the member 2 willturn the ratchet wheel 64 and cam into a position for contact with theroller 66. The parts are sotimed that the roller 66 is actuated downwardby 0 the downward movement of the member 2 and lug 59, it beingunderstood that said lug will actuate the bell crank 60 twice in eachcycle, first in the upward movement and second, in the downwardmovement. Thus at the completion of the,work 25 cycle and after the workhas been withdrawn from contact with the grinder wheels, the valve 69 isoperated to effect the trimming. This as previously described consistsin first lowering the head 10 and trimmer shaft 11 to bring the diamondtrimming point 13 into the common axial plane of the grinder wheels;second, to impart a rotary motion to the shaft 11 and the diamond 13 andthird, to feed the grinder wheels towards each other a sufficient amountfor the trimming. The nextactuation of the handle 46 will upon theinitial upward movement of the member 2 again actuatethe bell crank 60by the lug 59 which releases the roller 66 from the cam 65 permittingthe return movement of the valve 69 by the spring 98 and the consequentrestoration of the trimmer shaft to its normal position where it willnot interfere withthe work. I

What I claim as my invention is: v 1. A grinding machine comprising aframe, a plurality of grinder wheels mounted thereon with peripheralportions thereof in proximity, a trimmer and a work holder mounted onsaid frame and adiustable along a common axis passing between theperipheral portions of said H der wheels, means for moving said trimmerbetween and in the axial plane of said grinder wh'eelsand for rotatingthe same in this plane to fashion; the cross sectional contours of saidwheels and means for moving said work holder to feed the work betweensaid grinder wheels.

2. In a grinding machine, the combination with a frame, of a pair ofgrinder wheels mounted on said frame to rotate in the same plane withperipheral portions thereof in proximity, means for periodicallyadjusting the axes of said wheels towards each other, a trimmer movableperiodically between said wheels into the axial plane thereof androtatable to trim said wheels to a predetermined crossv sectionalcontour, a work holder in axial alignment with said trimmer and meansfor reciprocating said work holder along said axis to carry successivepieces of work betrimmer for fashioning the peripheral portion of saidwheels to a predetermined cross sectional contour, and means operatingperiodically after a predetermined number of reciprocations of said workholder. for operating said trimmer.

4. In a grinding machine, the combination with a frame, of a pair ofgrinder wheels mounted on said frame to rotate in the same plane andwith peripheral 'portions thereof in proximity, a work holder movablealong an axis extending between the adjacent peripheral portions of saidgrinder wheels, a hydraulic motor for reciprocating said work holder, atrimming mechanism for fashioning the cross sectional contour of saidgrinder wheels, hydraulic means for operating said trimmer and meansoperating after a predetermined number of reciprocations of said workholder for operating said hydraulic actuating means for said trimmer.

5. In a grinding machine, the combination with a frame, of a pair ofgrinderwheels mounted on said frame to rotate in a common plane and withperipheral portions thereof in proximity, a work holder movable along anaxis passing between the adjacent peripheral portions of said grinderwheels, a hydraulic piston motor for reciprocating said work holder, avalve for admitting fluid under pressure to said motor on one side ofthe piston and for exhausting'fluid on the other side of said piston,manual means for actuating said valve to a position for admitting fluidunrestrictedly to move said work holder rapidly towards said grinderwheel, automatic means controlled by the position of said work holderduring the movement thereof for restricting the flow of fluid andretarding movement while the work is in engagement with the grinderwheels in its forward and return movements and for then opening thevalve for rapid return of the work holder to its initial position.

6. In a grinding machine, the combination with a frame, of a-pair of-grinde'r wheels mounted thereon to rotate in a common plane, and withperipheral portions thereof in proximity, a work holder movable along anaxis passing between the adjacent peripheries of said wheels, hydraulicmeans for reciprocating said work holder, a trimmer in axial alignmentwith said work holder on the opposite side of said grinder wheels, andmeans automatically actuated after a predetermined number ofreciprocations of said work holder for actuating said trimmer to movethe same between said grinder wheels in the common axial plane thereoffor rotating said trimmer while thus positioned to trimthe peripheriesof said wheels to a predetermined cross sectional contour and forwithdrawing the trimmer out of the path of the work.

7. In a grinding machine, the combination with a frame, of a pair ofgrinder wheels mounted thereon to rotate in a common plane withperipheral portions thereof in proximity, a work holder movable along anaxis passing between the adjacent peripheries of said wheels, means forautomatically reciprocating said work holder to carry the work betweensaid wheels, and a work clamp released in the normal position of saidwork holder and automatically engaging upon the movement thereof to holdthe work clamped during the grinding operation.

.8. In a grinding machine, the combination with a frame and a grinderwheel mounted there- .on, of a reciprocating member for carrying thework in operative relation to said grinder wheel, a work holdercarriedby said reciprocatory member including a socket for receiving a shank ofthe work, a spring actuated clamping member for holding the work in saidsocket while in operative relation to said grinder wheel, and a shankfor said clamping member engageable with a stop in the normal positionof said work holder to release the clamp and permit of engaging the workwith and disengaging it from said socket.

9. In' a grinding machine, the combination with a frame, a pair ofgrinderwheels mounted thereon to rotate in a common plane withperipheral portions thereof in proximity, a trimmer for said grinderwheels and hydraulic actuating mechanism for said trimmer comprising apiston motor for moving said trimmer axially of the trimming positionbetween said grinder wheels, a rotary motor for revolving said I trimmerwhile in trimming position and including a fluid actuated gear motor anda step-down transmission, a valve for controlling said hydraulicactuating mechanism adapted to successively admit fluid to said pistonmotor and to said gear motor, a reciprocating work holder for carryingthe work to and from operative relation to said grinder wheel, andtiming means automatically operated" by said reciprocating work holderfor periodically operating said valve to effect the trimming of thegrinder wheel.

10. In a grinding machine, the combination with a frame, of grinderwheels mounted thereon to rotate in a common plane with peripheralportions thereof in proximity, a work holder movable alongan axisextending between the peripheries of said wheels, means for successivelyreciprocating said work holder to carry the work between said wheels, atrimmer for fashioning the peripheral portions of said wheels to a.

,predetermined cross sectional contour, means for moving said trimmer inalignment with the axis of said work holder into trimming positionbetween said grinder wheels. means for rotating said trimmer while thuspositioned to eflect the trimming of the wheels, means for adjusting theaxes of said grinder wheels towards each other and mechanismautomatically operating after a predetermined number of reciprocationsof said work holder'for positioningsaid trimmer, rotating the same andfor feeding the axes of the grinder wheels towards each other.

11. In a grinding machine, the combination with a frame, and a pair ofgrinder wheels mounted to rotate in a common plane having peripheralportions thereof in proximity and a trimmer for said grinder wheelscomprisinga slide movable towards and from said grinder wheels, a rotarytrimmer shaft carried by said slide and moved axially thereby in betweensaid grinder wheels, a hydraulic motor for rotating said shaft, 9.rockable lever for reciprocating said slide, a piston slotted for thepassage, of said rockable lever, cylinders in which the'opposite ends ofsaid piston operate and means periodically operating for admitting fluidto said cylinders to actuate said rockable lever and slide carrying saidtrimmer shaft into operative position and for also admitting fluid tosaid hydraulic motor for rotating said shaft whereby the trimming ofsaid grinder wheels is effected.

FREDERICK A. WARD.

